Refrigerator embodying compact arrangement of air-cooled parts



June 3, 1952 we. KOGEL 2,593,703

REFRIGERATOR EMBODYING COMPACT ARRANGEMENT OF AIR-COOLED PARTS Filed 001- 6, 1947 2 Sl-IEETSSFEET 1 June 3, 1952 w, KQGEL 2,598,703

REFRIGERATOR EMBODYING COMPACT ARRANGEMENT 0F AIR-COOLED PARTS 2 Sl-lEETS-Sl-IEET 2 NVEN WM W 4 7M Patented June 3, 1952 TENT GFFICE REFRIGERATOR EMBODYING COMPACT ARRANGEMENT F AIR-COOLED PARTS Wilhelm Georg Kogei, Stockholm, Sweden, as-

signor to Aktiebolaget Elektrolux, Stockholm, Sweden, a corporation of Sweden Application October 6, 1947, Serial No. 778,095 In Sweden October 8, 1946 Claims.

My invention relates to refrigeration, and more particularly to absorption refrigeration systems of the type employing an inert gas or pressur equalizing agent.

It is an object of my invention to effect improvements insyst'erns of this type, particularly to obtain more efficient air cooling of the condenser and to provide a simple and compact arrangement of parts including the condenser which reduce the amount of space required by such parts when incorporated in a refrigerator cabinet of the household type. More particularly, it is an object to provide a compact arrangement of an air cooled condenser structure and a pressure vessel from which liquid refrigerant can flow by gravity to a cooling element. whereby the overall height of the refrigeration system will be at a, minimum.

I accomplish this by providing an air cooled condenser having a looped coil including straight sections or portions which are disposed alongside of and thermally connected alon their length to spaced apart plates which form relatively extensive heat dissipating surfaces for cooling refrigerant fluid flowing through the coil. With such a thermal connection between the straight coil sections and the plates, a metallic heat conductive path is obtained for effectively dissipating heat from the wall surfaces of the straight coil sections with the aid of the plates over which air circulates, whereby efficient cooling and condensing'of refrigerant fluid is accomplished.

The spaced apart plates to which the straight sections of a looped condenser coil are thermally connected are preferably arranged to form a passage through which circulation of air is induced by natural draft. In absorption refrigeration systems of the inert gas type employing a pressure vessel, such vessel can be located and positioned in the space or passage between the plates and below the upper edges thereof, whereby part of the condenser structure vertically overlaps the vessel. By positioning and locatingthe pressure vessel at a level which is within the vertical height taken up by the condenser structure, a compact arrangement is obtained in which the overall height of the refrigeration system is at a minimum.

The invention; together with the above and other objects and advantages thereof, will be more fully understood upon reference to the following description and accompanying drawings forming apart of this specification, and of which:

Fig. 1 illustrates more or less diagrammatically an absorption refrigeration system of the inert as type embodying the invention;

Fig. 2 is a fragmentary side vertical sectional View of a refrigerator cabinet with which parts of the refrigeration system of Fig. 1 are incorporated and illustrated in elevation;

Fig. 3 is an enlarged fragmentary view in elevation, partly broken away and in section, of parts of the refrigeration system illustrated in Fig. 2, as seenfrom the rear of the refrigerator cabinet;

and

Fig. 4 is an end View in elevation of the parts shown in Fig. 3. 7

Referring to Fig. 1, the invention is embodied in an absorption refrigeration system of a uniform pressure type containing an inert gas or pressure equalizing agent. A system of this type includes a generator 18, condenser Ii, cooling element or evaporator i2 and an absorber [4 which are interconnected in a manner well known in the art and which will briefly be described hereinafter. The system contains a solution of refrigerant in absorption liquid, such as ammonia in Water, for example, and also an auxiliary agent or inert gas, such as hydrogen.

The generator Ill is heated in any suitable manner, as by a gas burner l5, for example; which projects its flame into the lower end of a flue It with which the generator Hi is in thermal contact. By heating the generator to, refrigerant Vapor is expelled out of solution and flows upwardly through conduit [1 into the air cooled condenser H, which presently will be described in 'detail. Refrigerant liquefied in the condenser H flows therefrom through a conduit l8 having a liquid trap i9 into the upper part of the evaporator or cooling element 1 2 and evaporates and diffuses therein into inert gas to produce a refrigerating effect. The rich gas mixture of refrigerant and inert gas flows from evaporator [2 through a conduit 25!, gas heat exchanger 2|, conduit 22 and abscrbervessel 23 into the lower end of an air'cooled absorber M which is in the form of a looped coil.

In absorber M the rich gas mixture flows counter-current to downwardly flowing weak absorption liquid which enters through a conduit 2%. The absorption liquid absorbs refrigerant vapor from inert gas, and inert gas weak in refrigerant flows from absorber [4 through conduit 25 and gas heat exchanger 2! back to the lower part of the evaporator l2. Absorption liquid onriched. in refrigerant flows from the lower part of absorber l 4 into the vessel 23. From the vessel 23 enriched absorption liquid is conducted through a conduit 26 and a liquid heat exchanger 2? to a vapor lift or thermosyphon tube 28 in thermal contact with the flue I 5.

Liquid is raised by vapor lift action through through liquid heat exchanger 21 and conduit 24 into the upper part of absorber 14. This circulation of absorption liquid is effected by raisin i of liquid in tube 28 by vapor lift action. I

A vessel 29 is connected by a conduit 30 to'the lower part of condenser I I and by a conduit 3| to I the gas circuit, as at the gas heat exchanger 2I, for example, so that any inert gas which may I pass into the condenser can'fiow into the gas circuit. The vessel 29, which is referred to as a pressure vessel, serves as a storage chamber for 1 a reserve supply of inert gas and under normal 3 operating conditions is filled with substantially pure inert gas. Refrigerant vapor not liquefied (in condenser II, due to increase in temperature of air effecting cooling of the condenser, flows "through conduit 30 to displace inert gas in vessel 29 and force such gas through conduit 3I'into the gas circuit. This increases the total pressure in the system so that an adequate condensing pressure is obtained to insure condensation of refrigerant vapor in condenser II.

In Fig.2 a practical embodiment of the in- 1 vention is diagrammatically shown wherein the system in Fig. 1 is incorporated in a household refrigerator. The evaporator I2 is disposed in an enclosed space 32 of a thermally insulated refrigerator cabinet 33. In order to position the evaporator within the space 32, the rear wall 34 1 of the, cabinet is formed with an opening 35 whichis adapted to be closed by a closure member 36 through which extend the connections be- I tween the evaporator'and other parts of the re- ;frigeration system positioned exteriorly of the insulated space 32 at the rear of the cabinet 33. The generator I0, flue I6, vapor lift tube'28 and 3 liquid heat exchanger 21 .are embedded in suit able insulating material contained within a metal casing or shell 3'! positioned adjacent to the wall 1 I 34 at the rear of the cabinet 33. The shell 31 is 1 provided with openings at the top and bottom thereof through which project the open ends of the heating flue I6. The absorber coil I4 and inet 33.

In accordance with my invention,.structure is 1 provided for effectively cooling condenser II whereby the latter will operate efficiently to con- 7 I dense refrigerant vapor suppled thereto from the generator III and deliver condensate to the v 3 evaporator I2. The condenser II comprises pipj ing in the form of a looped coil having straight sections 38 disposed in spaced apart vertical planes which are connected by a return bend 39. The straight sections 38 are substantially h'ori zontal and at different levels, and the return bend 39 is inclined and connects the higher cated straight section in one vertical'plane to the lower straight section in the other vertical plane. 7

To the'straight sections 38 of the looped coil I accomplish this ing or brazing, for example, to the inner opposing surfaces of the plates 40 and M. The channel members 42 snugly receive the straight sections 38 of the looped coil and are secured in position, as'by seam welding, for example, to

provide a good thermal conductive connection between the straight coil sections and the heat dissipating plates 40 and M. V

The condenser II is located at the rear wall 34 of the cabinet 33 and is desirably positioned so that the plates 40 and M are vertically disposed above the absorber coil I4. To facilitate mounting the condenser II at the rear wall 34 of the cabinet, the opposing vertical edges of the a plate 40 may be provided with integrally formed brackets 43 which may be secured in any suitable manner to the rear wall 34. The conduit I! through which refrigerant vapor flows from the generator I0 extends upwardly at one end of the condenser- I I and is bent to provide a more or less horizontally extending section IIa. The conduit section I'Ia extends across the rear of the cabinet 33 in the gap between the rear wall 34 and the plate 40, and at the end thereof remote from generator I0 is connected at 44 to a return bend 45 of the condenser coil through which replate M.

The horizontal conduit section I'Ia includes upwardly and downwardlyinclined portions between which an indent is formed. The upwardly inclined portion of conduit section I'Ia serves'as an air cooled rectifier in which is condensed any absorption liquid vapor which may be carried upward with the refrigerant vapor, and such condensate drains back to the generator I0 and is prevented from passing into the condenser II by the indent 45 which more or less forms a dam or barrier intermediate the ends of horizontal conduit I'Ia. .Liquid refrigerant flows from the condenser I I through the conduit I8 into the upper part of the evaporator I2, as

' previously explained. As best shown in Figs. 3

and 4, the conduit I8 is connected to the condenser at 46 and at a bent portion intermediate at the ends thereof passes through a notch 41 formed at the bottom of plate 40.

When the refrigeration system is operating, refrigerant vapor is condensed in the condenser coil I I due to the cooling influence of the surrounding air which passes over the surfaces of the coil and plates 40 and 4|. Since a good metallic heat conductive path is provided between the walls of the straight coil sections 38 and the plates 40 and 4| along the entire length of the latter, the heat of condensation resulting from the condensing of refrigerant vapor is effectively given up to the surrounding air which passes over and in intimate contact with the surfaces of the plates 40 and 4|. With heat eifectively transmitted from the straight coil sections 38 along the entire length thereof thermally connected to the plates 40 and 4|, the condenser will operate efllciently to condense refrigerant vapor supplied thereto.

By employing the spaced apart plates 40 and II to provide relatively extensive heat dissipating surfaces for the condenser coil, a passage is formed therebetween through which circulation of surrounding air over the plate surfaces is promoted due to the upward flow of air in the passage which is induced by natural draft. When the refrigeration system is operating, heat is also liberated in the absorber coil I4 due to absorption of refrigerant vapor into absorption liquid. Such heat .of absorption is given up to surrounding air which passes over the surfaces of the absorber coil. Since the condenser coil H and plates and 4| fixed thereto more or less provide an unobstructed path of flow for surrounding air at the rear of the cabinet '33, air heated as a result of passing over the surfaces of the absorber coil can freely rise in the space at the rear of "the cabinet and readily pass through the passage formed between the plates 40 and 4|. In addition, an arrangement is provided which readily permits surrounding cooling air, unheated by previous dissipation of heat of absorption, to circulate and pass over the extensive heat dissipating surfaces formed by the plates 49 and 4|.

By employing an air cooled condenser like that just described, important advantages are realized in that it provides a desirable space for positioning and locating the pressure vessel 29. As best shown in Fig. 2, the pressure vessel 29 is located at the rear of the cabinet 33 in the ap or space between the plates 40 and 4| at a level well below the upper edges of the plates. Hence, the pressure vessel 29 and air cooled condenser structure vertically overlap each other at the rear of the cabinet 33 to provide a compact arrangement of parts in which the overall height of the refrigeration apparatus is at a minimum,

the arrangement being such that liquid refrigerant can flow by gravity from the pressure vessel through conduits 39 and i8 into the evaporator, as will be described presently. Since the parts of a refrigeration system of a given capacity will occupy a space of minimum overall height at 1 the rear of the cabinet, the cabinet itself can be of minimum overall height and its height does not need to be increased unnecessarily simply to provide adequate housing space at the rear thereof to take care of the pressure vessel when the latter is to be positioned to drain liquid refrigerant therefrom by gravity flow into the evaporator.

It has previously been pointed out that refrigerant vapor not liquefied in the condenser passes into the pressure vessel 29 through the conduit 30. When this occurs the pressure vessel 29 functions as an extension of the condenser H or as an auxiliary condenser due to the cooling influence of the surrounding air which passes over the surfaces of such vessel. Refrigerant liquefied in the vessel 29 flows by gravity through conduits 39 and |8 into the evaporator l2. By positioning the pressure ves sel 29 in the space or passage formed between the plates 49 and 4| through which circulation of air is induced by natural draft, effective cooling of the vessel is accomplished and the latter will be maintained at a low temperature and operate efficiently as an auxiliary condenser. 3

The size of the pressure vessel 29 employed and the spacing of the plates 40 and 4| may be such that a narrow gap is provided between each side of the vessel and the plate adjacent thereto to obtain a throttling effect which will increase and accelerate the natural draft circulation of cooling air past the surfaces of the condenser structure, thereby effectively promoting the dissipation of heat and giving up of such heat to the cooling air.

In view of the foregoing, it will now be understood that I have provided an improved air cooled condenser structure which requires a minimum number of parts; By" employing plates 40 and 4| which are in good metallic heat conductive connection with the straight 'co'il sections throughout their length, heat is effectively dissipated from surface portions of the walls of the straight coil sections. in the embodiment of the invention illustrated and described, the metallic heat conductive path between the straight coil sections and the cooling plates is accomplished by seam welding these parts together, the U- shaped channel members 42 fixed to the plates facilitating the proper positioning of the straight coil sections with respect to the plates, whereby providing a simple construction is provided which is inexpensive :and easily manufactured.

Modifications of the embodiment of my inven-' tion which I have described will occur to those skilled'in the art, so that I desire my invention not to the limited to the particular arrangements set forth. For example, the number of straight coil section's thermally connected to each plate may be varied and spaced apart so that refrigerant will pass downwardly from each straight coil section at one plate to another straight coil section at the opposite plate. Further, the straight coil sections of the condenser coil may be disposed one above another and thermally connect ed to the same plate, and the straight coil sec tions fixed to each plate may form parts of condenser coils connected in parallel. Moreover, the straight coil sections may be fixed to the outer faces of the spaced apart plates as well as to the inner opposing faces, and the plates may be disposed in positions deviating from a vertical position. Therefore, I intend in the claims to cover all those-modifications which do not depart from th spirit and scope of my invention.

What is claimed is:

1. An absorption type refrigeration system comprising an evaporator in which refrigerant fluid evaporates in the presence of an inert gas and a condenser unit including piping for refrigerant fluid having horizontally extending sections in different vertical planes, and spaced apart vertically extending plates thermally connected to such sections, each horizontally extending pipe section only having a single vertically extending plate thermally associated with different regions along the length thereof, said spaced apart plates each having a height substantially co-extensive with the overall height of said condensing unit and serving as heat dissipating surfaces for cooling fluid flowing through said coil and forming condensate therer 3. A refrigerator comprising a cabinet having a thermally insulated storage space, absorption type refrigeration apparatus including an evaporator employing evaporation of refrigerant fluid into inert gas which is arranged to effect cooling of the space and an air cooled condenser unit comprising piping for refrigerant fluid formed with substantially straight sections which are in different vertical planes and extend alongside the rear wall of the cabinet at the exterior thereof, and spaced apart vertically extending'plates vertically extending plate thermally associated said plates each having a height substantially cocoil.

a 4. A refrigerator comprising a cabinet having a thermally insulated storage space, absorption type refrigeration apparatus including an air 1 cool'ed condenser structure comprising a pair of spaced apart vertically extending plates disposed exteriorly of the cabinet at the rear thereof and 1 thermally connected to said straight pipe sections, each straight pipe section having a single I with different regions along the length thereof,

unobstructedly exposed in their entirety to am- 3 bient air, piping for refrigerant fluid having horizontally extending sections in different vertical planes, each horizontally extending pipe section along the length thereof being thermally connected only to one of said plates, said plates each having a height substantially co-extensive 1 'with the overall height of said condenser structure and serving as heat dissipating surfaces for cooling the fluid flowing through said'piping and providing a passage therebetween through which i 5 circulation of air is induced by natural draft.

5. A refrigerator comprising a cabinet having a thermally insulated storage space, absorption type refrigeration apparatus having a circuit for absorption liquid including a generator and an receive refrigerant fluid from said generator and deliver condenser refrigerant to said evaporator, and said condenser structure comprising a pair of spaced apart vertically extending plates and f piping: for the fluid having straight sections in diiferent vertical planes, each straight pipe sec- 7 tionalong the length thereof being thermally connected only to one of said plates, said plates I ceive air previously heated by said absorber;

; serving as heat dissipating surfaces for cooling: the fluid flowing through said piping and proividing a passage therebetween arranged to re- 6. An absorption type refrigeration system having a plurality of interconnected parts providing circuits for circulating absorption liquid, refrigerant and inert gas and including an air cooled condenser connected to receive refrigerant vapor and an evaporator connected to receive liquid refrigerant from said condenser, a pres- 1 sure vessel connected to said condenser and to said gas circuit and arranged to deliver to said evaporator by gravity flow'refrigerant condensed therein, said condenser including structure comprising a pair of spaced apart vertically extending plates and a looped coil having horizontally extending straight sections alongside of and in thermal contact with said plates, and said pressure vesselibeing located in the space between said plates at a level below the top edge of the uppermost plate. 7

1 7. An absorption type refrigeration system V 31 comprising a plurality of interconnected parts providing circuits for circulating absorption liquid; refrigerant and inert gas, said parts including an air cooled condenser comprising spaced apart vertically extending plates andna looped coil having horizontally extending sections in thermal contact with said plates, the top edge of one of said plates being at a higher level than that'of saidother plate, and another of said parts being located in the space between said plates at alevel below the top edge of said plate at the higher level.

8. A refrigerator comprising a cabinet having thermally insulated walls, an absorption type refrigeration system having a plurality of interconnected parts providing circuits for circulating absorption liquid, refrigerant and inert gas and including an air cooled condenser provided with'a fluid passageway connected to receive refrigerant vapor and an evaporator for cooling the interior of the cabinet which is connected to receive liquid refrigerant from said condenser,

an elongated pressure vessel connected to said fluid passageway and to said gas circuit and arranged to deliver to said evaporator by gravity floW refrigerant condensed therein, said condenser comprising structure including a looped coil and cooling fins forming a vertically extending passage between different parts of said coil, said cooling fins being positioned at the exterior of the cabinet to enable air to pass in intimate contact with the opposing faces of each cooling fin, said coil having portions thereof in the direction of its length disposed alongside of and in the immediate vicinity of said cooling fins, such coil portions in the direction of' their length being heat conductively connected to. said cooling fins, and said vessel being substantially parallel to said cooling'fins and in vertical alignment with the passage therebetween and having at least apart thereof below the uppermost edge of said cooling fins.

9. An absorption refrigeration system comprising a plurality of air cooled parts including a refrigerant liquefier, said liquefier comprising spaced apart vertically extending plates serving as heat dissipating surfaces, and a looped coil having horizontally-extending sections alongside of and inthe immediate vicinity of said plates, such coil sections in the direction of their length being heat conductively connected to said plates, and another of said parts being located in the space between said plates.

10. A refrigerator comprising a cabinet having a thermally insulated interior, absorption refrigeration apparatus having a circuit for absorption liquid including a, generator and an air cooled absorber, a circuit for pressure equalizing gas including said absorber and an evaporator arranged to abstract heat from the interior of the cabinet, an air cooled condenser which is connected to receive refrigerant fluid from said generator and deliver condensed refrigerant to said evaporator, a vessel serving as an extension of said condenser which is connected thereto and to said gas circuit and arranged. to deliver to said evaporator by gravity flow refrigerant condensed therein, said condenser comprising spaced apart vertically extending plates and a looped coil having horizontally extending sections alongside of and in the immediate vicinity of said plates, such coil sections in the direction of their length being heat conductively connected to said plates, said'vessel being located in the space between said plates, and said condenser, vessel and 9 10 absorber being disposed exteriorly of the cabinet, UNITED STATES PATENTS said plates providing a passage therebetween to receive air previously heated by said absorber Number Name Date and each of said plates having both faces thereof 2,037,78 Hainsworth Apr. 21, 1936 exposed to air which can pass in intimate contact 2,053,292 Bergholm 1936 therewith. 2,164,045 Ullstrand et a1. June 27, 1939 WIL M GE KOGEL 2,194,505 Kogel et a1 Nov. 26, 1940 2,313,707 Lithgow et a1 Mar. 9, 1943 REFERENCES CITED 2,350,249 Osborn May 30, 1944 The following references are of record in the 10 file of this patent: 

